Amino group containing phenol derivative

ABSTRACT

An object of the present invention is to provide a material which resolves the drawbacks associated with polyimide polymers, and yet retains the advantages offered by conventional polyimide polymers.  
     An amino group containing phenol derivative of the present invention is represented by a general formula (1) show below, and the present invention also provides a polyimide precursor produced using such an amino group containing phenol derivative.  
                 
 
     (wherein, R 1 , R 2  and R 3 , which may be the same or different, each represent an alkyl group of 1 to 9 carbon atoms, an alkoxy group of 1 to 10 carbon atoms, a COOR group (in which R represents an alkyl group of 1 to 6 carbon atoms) or a hydrogen atom; R 4  and R 5 , which may be the same or different, each represent an alkyl group of 1 to 9 carbon atoms or a hydrogen atom; X represents —O—, —S—, —SO 2 —, —C(CH 3 ) 2 —, —CH 2 —, —C(CH 3 )(C 2 H 5 )—, or —C(CF 3 ) 2 —; and n represents an integer of 1 or greater).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an amino group containing phenolderivative, as well as a polyimide precursor or a polyimide polymer; aphotosensitive polyimide precursor or a photosensitive polyimidepolymer; and a composite-material using the same.

[0003] 2. Description of the Related Art

[0004] In recent years, advances in IT equipment functionality havecreated a demand for increased density within mobile equipment capableof processing enormous quantities of information. Furthermore,considerable focus is now being placed on the environmental impact ofthe materials used in the production of these types of electroniccomponents, and the demands continue to become increasingly tight withcalls for halogen free flame proofing and improved heat resistance forlead free solders and the like. Specific requirements include lowstress, low dielectric constant, high heat resistance, good adhesion andgood flame resistance. Furthermore polyimide polymers, which are usedconventionally in electronic components for functions such as thesurface protective films and interlayer insulation films ofsemiconductor elements, display excellent heat resistance, mechanicalcharacteristics and flame resistance, as well as a low dielectricconstant, good flame resistance, good ease of application, and good filmforming properties, and as a result have been widely mooted as potentialmaterials for next generation applications. However, current polyimidepolymers have significant drawbacks including having poor adhesion(adhesiveness) with silicon wafers and metal oxide and the like, anddisplaying a large degree of thermal expansion following glasstransition. Furthermore, modifications of polyimide polymers have proveddifficult, and because such polyimide polymers are also only sparinglysoluble in organic solvents, their workability is poor, and potentialapplications have remained comparatively limited. In order to improve onthese drawbacks associated with polyimide polymers, Japanese UnexaminedPatent Application, First Publication No. Hei 5-255480 discloses wellbalanced epoxy modified polyimide polymers which are able to maintainthe inherent heat resistance of the polyimide polymer while alsoensuring good flame resistance. In addition, Japanese Unexamined PatentApplication, First Publication No. Hei 6-345866 discloses siloxanemodified polyimide polymers in which a siloxane skeleton is introducedinto the main polyimide chain in order to produce lower stress values.

[0005] However, in the epoxy modified polyimide polymers disclosed inJapanese Unexamined Patent Application, First Publication No. Hei5-255480, the molecular weight, the ease of application and themechanical characteristics of the polyimide polymer actuallydeteriorate, and the desired characteristics are not satisfactorilyachieved. Furthermore, in the siloxane modified polyimide polymersdisclosed in Japanese Unexamined Patent Application, First PublicationNo. Hei 6-345866, the heat resistance deteriorates as a result of thesiloxane modification, and some loss occurs in the inherentcharacteristics of the original polyimide polymer. The present inventiontakes these issues into consideration, with an object of providing amaterial which resolves the drawbacks associated with conventionalpolyimide polymers such as poor substrate adhesion and unsatisfactoryflexibility, and yet retains the advantages offered by conventionalpolyimide polymers.

SUMMARY OF THE INVENTION

[0006] The inventors of the present invention conducted intensiveresearch aimed at remedying the unsatisfactory characteristics of thepolyimide polymers described above, on the premise that complexes formedwith other compounds may be effective in this regard. However, becauseconventional polyimide polymers and materials formed therefrom displaypoor reactivity with other compounds, this type of improvement provedextremely difficult. However on further investigation, the inventorsdiscovered that by introducing a phenol compound into a polyimidepolymer using an amino group containing phenol derivative, the formationof complexes with other compounds became possible, and theunsatisfactory characteristics of the polyimide polymer could beremedied by a complexed compound thereof, and were hence able tocomplete the present invention. In other words, an amino groupcontaining phenol derivative of the present invention is an amino groupcontaining phenol derivative represented by a general formula (1) showbelow.

[0007] (wherein, R¹, R² and R³, which may be the same or different, eachrepresent an alkyl group of 1 to 9 carbon atoms, an alkoxy group of 2 to10 carbon atoms, a COOR group (in which R represents an alkyl group of 1to 6 carbon atoms) or a hydrogen atom; R⁴ and R⁵, which may be the sameor different, each represent an alkyl group of 1 to 9 carbon atoms or ahydrogen atom; X represents —O—, —S—, —SO₂—, —C(CH₃)₂—, —CH₂—,—C(CH₃)(C₂H₅)—, or —C(CF₃)₂—; and n represents an integer of 1 orgreater.)

[0008] Furthermore, a polyimide precursor of the present invention isformed from a repeating unit represented by a general formula (2) shownbelow.

[0009] (wherein, R¹, R² and R³, which may be the same or different, eachrepresent an alkyl group of 1 to 9 carbon atoms, an alkoxy group of 2 to10 carbon atoms, a COOR group (in which R represents an alkyl group of 1to 6 carbon atoms) or a hydrogen atom; R⁴ and R⁵, which may be the sameor different, each represent an alkyl group of 1 to 9 carbon atoms or ahydrogen atom; X represents —O—, —S—, —SO₂—, —C(CH₃)₂—, —CH₂—,—C(CH₃)(C₂H₅)—, or —C(CF₃)₂—; R⁶ represents an aromatic tetracarboxylicdianhydride group; and n represents an integer of 1 or greater.)

[0010] Furthermore, a polyimide polymer of the present invention isobtained via a dehydration condensation reaction of an aforementionedpolyimide precursor. Furthermore, a polyimide precursor or a polyimidepolymer of the present invention may also be a photosensitive polyimideprecursor or a photosensitive polyimide polymer in which a hydrogen atomof at least one phenolic hydroxyl group is substituted with a functionalgroup which imparts photosensitivity to the polyimide precursor. Inaddition, a polyimide precursor or a polyimide polymer of the presentinvention may also be complexed with another compound to form acomposite material

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an IR spectrum of a product of a synthetic example 1.

[0012]FIG. 2 is an IR spectrum of a product of a synthetic example 2.

[0013]FIG. 3 is an IR spectrum of a product of a synthetic example 3.

[0014]FIG. 4 is an IR spectrum of a product of a synthetic example 4.

[0015]FIG. 5 is an IR spectrum of a product of a synthetic example 5.

[0016]FIG. 6 is an IR spectrum of a product of a synthetic example 6.

[0017]FIG. 7 is an IR spectrum of a product of an example 1.

[0018]FIG. 8 is an IR spectrum of a product of an example 2.

[0019]FIG. 9 is an IR spectrum of a product of an example 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] As follows is a more detailed description of the composition ofthe present invention.

[0021] (A) Amino Group Containing Phenol Derivative

[0022] In an amino group containing phenol derivative according to theaforementioned general formula (1), the groups R¹, R² and R³ within theformula represent either:

[0023] (i) a straight chain or a branched chain alkyl group of 1 to 9carbon atoms, and preferably 1 to 4 carbon atoms;

[0024] (ii) an alkoxy group of 1 to 10 carbon atoms, and preferably 1 to4 carbon atoms (in which the alkyl group of the alkoxy group may beeither a straight chain or a branched chain);

[0025] (iii) a COOR group (in which R represents a straight chain or abranched chain alkyl group of 1 to 6 carbon atoms, and preferably 3 to 6carbon atoms); or

[0026] (iv) a hydrogen atom, and the groups R¹, R² and R³ may be eitherthe same or different.

[0027] Of these options, the case in which R¹, R² and R³ represent alkylgroups enables the water resistance to be improved. In the case ofalkoxy groups or COOR groups, the adhesion of the compound to asubstrate can be improved, for those cases in which the compound is usedin electronic components, as described below. Furthermore, in the caseof COOR groups, complexing with polyesters to form composite materialsalso becomes possible, as described below. In addition, hydrolysis ofeither the alkoxy groups or the COOR groups enables the alkalisolubility to be further improved, which is desirable for applicationsto alkali developing type uses. In other words, the groups R¹, R² and R³should preferably be selected in accordance with the desiredapplication. Compounds in which either one or two of the groups R¹, R²and R³ are hydrogen atoms, and the remainder are groups other thanhydrogen atoms, display particularly preferred characteristics.Furthermore, the group or groups which are not hydrogen atoms shouldpreferably be methyl groups. For example, combinations in which two ofR¹, R² and R³ are hydrogen atoms and one is a methyl group, orcombinations in which one of R¹, R² and R³is a hydrogen atom and theother two are methyl groups produce improvements in moisture resistance,and are consequently preferred.

[0028] In addition, the groups R¹, R² and R³ may be bonded to any of thecarbon atom positions from 2 to 6 shown in the general formula (1),although in cases in which a regular repeating unit is required,compounds with good structural symmetry are preferred. Particularly inthose cases in which two of the groups R¹, R² and R³ are hydrogen atomsand the other one is a group other than a hydrogen atom, bonding thenon-hydrogen atom group to the respective carbon atoms at position 4generates better structural symmetry, and is consequently preferred forcases in which a regular repeating unit is required. Furthermore, if allof the groups R¹, R² and R³ are methyl groups then the moistureresistance can be improved even further, and the solubility in solventsalso improves.

[0029] The groups R⁴ and R⁵ represent either a straight chain or abranched chain alkyl group of 1 to 9 carbon atoms, and preferably 1 to 4carbon atoms, or a hydrogen atom, and may be either the same ordifferent. By introducing an alkyl group at R⁴ and/or R⁵ in this manner,the water resistance of the compound can be improved. Furthermore, fromthe viewpoint of reactivity of the amino groups, R⁴ and R⁵ shouldpreferably be methyl groups.

[0030] In addition, if the R⁴ groups, the R⁵ groups, and the X and —CH₂—groups bonded to the respective benzene rings comprising the twoterminal amino groups are bonded to the same number carbon atom in eachcase, and if the benzene rings to which the two terminal amino groupsare bonded, and the —X— and —CH₂— groups linking these benzene rings tothe benzene ring or rings to which a phenolic hydroxyl group is bonded,are symmetrical in each case, then a high molecular weight polyimideprecursor can be formed, which is desirable. X represents —O—, —S—,—SO₂—, —C(CH₃)₂—, —CH₂—, —C(CH₃)(C₂H₅)—, or —C(CF₃)₂—, although ofthese, a —CH₂— linkage results in a simpler reaction process, and isconsequently preferred. In a preferred configuration, (i) the two R⁴groups are each bonded to the respective carbon atom at either position2 or position 6, (ii) the two R⁵ groups are each bonded to the otherrespective carbon atom at either position 2 or position 6, and (iii) Xand the methylene group are each bonded to the respective carbon atom atposition 4. In such a configuration, because the hygroscopicity of theamino groups is guarded, the moisture resistance improves, and moreoverbecause there is no interaction between the amino groups and an adjacentphenolic hydroxyl group, the reactivity of the amino group increases,which is also desirable.

[0031] n represents any integer of 1 or greater, although in actualpractice is restricted to an integer of no more than 20. Furthermore,integers of 1 or greater, but no more than 15 are even more preferred.The actual value of n can be selected in accordance with the desiredcharacteristics of the final product.

[0032] Examples of the most preferred configurations for amino groupcontaining phenol derivatives of the present invention are shown below.

[0033] (n is preferably from 1 to 20)

[0034] A production method for an amino group containing phenolderivative of the present invention is described below for the case inwhich X is a —CH₂— group in the aforementioned general formula (1). Inthe production of this amino group containing phenol derivative,formalin is reacted with a phenol based compound represented by a[formula a] shown below (namely, a compound based on the general formula(1) in which the benzene rings to which the amino groups are bonded, X,and the methylene group have been excluded) and forms a dimethylolphenolderivative containing two bonded —CH₂OH groups, represented by a[formula b] shown below. In the general formula represented by the[formula b], if n represents a value of 2 or greater, then the structurecomprises two or more phenol based compounds connected via a methylenegroup. The value of n can be varied depending on the characteristics ofthe raw material phenol based compound represented by the [formula a],and the reaction conditions. Subsequently, the two —CH₂OH groups of thisdimethylolphenol derivative are subjected to a condensation with theamino group of an aniline derivative represented by a [formula c] shownbelow, yielding the amino group containing phenol derivative representedby the aforementioned general formula (1).

[0035] The groups R¹, R ², R³, R⁴ and R⁵, and the number n in theformulas from [formula a] through [formula c] are the same as thoseshown in the general formula (1), and can be appropriately selected inaccordance with the desired amino group containing phenol derivative tobe produced.

[0036] As follows is a description of a specific example of the reactionconditions. A phenol based compound and an aqueous solution of formalin(preferably with a concentration of approximately 50 mass %) containing2 to 4 times the number of mols of the phenol based compound are placedin a reaction vessel equipped with a stirrer, a thermometer, a condenserand a dropping funnel, and with the mixture undergoing constantstirring, alkali is then added dropwise to the mixture under reactionconditions including a temperature of 0 to 50° C. and a reaction time of1 to 2 hours. The alkali is preferably an alkali aqueous solution ofsodium hydroxide or potassium hydroxide or the like, and can utilize,for example, an aqueous sodium hydroxide solution with a concentrationof approximately 30 mass %. Furthermore, the quantity of alkali istypically an equivalent number of mols to the phenol based compound.After addition of the alkali, the temperature is raised, and thereaction is allowed to proceed at a reaction temperature of 20 to 80° C.for a period of 2 to 4 hours.

[0037] Subsequently, the reaction mixture is cooled, preferably to atemperature of no more than 30° C., neutralized with acid, and theproduct is precipitated. There are no particular restrictions on theacid used, and a suitable example is an aqueous acetic acid solutionwith a concentration of approximately 10 mass %. The product is thenfiltered, washed with water, and then dried under reduced pressure,preferably at a temperature of no more than 50° C., yielding the product(a dimethylolphenol derivative). This product, together with an anilinederivative, an acid catalyst, and where necessary an organic solvent, isthen placed in a reaction vessel equipped with a thermometer, acondenser and a stirrer, and is reacted for a period of 4 to 8 hours ata temperature of 120 to 200° C., and preferably 140 to 180° C.

[0038] The quantity of the aniline derivative used should be 2 to 4times, and preferably 2.2 to 3.0 times the number of mols of thedimethylolphenol derivative. The acid catalyst may utilize any typicalorganic acid or inorganic acid, and suitable examples includehydrochloric acid, paratoluenesulfonic acid and oxalic acid, although ofthese, oxalic acid is preferred. The quantity of the acid catalyst canbe altered appropriately depending on the type of acid used, although inthe case of oxalic acid, a quantity of approximately 1 mass % relativeto the total quantity of the materials in a reaction vessel ispreferred. Furthermore, although an organic solvent is not a necessity,using a solvent such as an alcohol, a cellosolve or toluene ispreferred. The quantity of the solvent is typically from 10 to 20 mass %relative to the total quantity of the reactants. Following reaction, themixture is cooled, and then purified where necessary using knowntechniques such as distillation or recrystallization, to yield an aminogroup containing phenol derivative according to the present invention.Examples of suitable solvents for the recrystallization includecellosolves, alcohols, acetate esters, benzene and toluene.

[0039] In those cases in which X in the aforementioned general formula(1) is a linkage group other than a —CH₂— group, an amino groupcontaining phenol derivative can be produced by using a phenol basedcompound such as bisphenol-S, hydroxydiphenyl ether or bisphenol AF, andthen performing a dimethylolation and reacting the product therefromwith an aniline derivative in the same manner as that described above.

[0040] (B) Polyimide Precursor and Polyimide Polymer

[0041] A polyimide precursor of the present invention is formed from arepeating unit represented by the aforementioned general formula (2).Furthermore, when this precursor is subjected to a dehydrationcondensation reaction, the two carboxyl groups and the imino groupbonded to the R⁶ group in the general formula (2) undergo respectivedehydration condensations, forming ring structures and generating apolyimide polymer formed from a repeating unit represented by a generalformula (3) shown below.

[0042] In the general formulas (2) and (3), the groups R¹, R², R³, R⁴,R⁵ and X, and the number n are the same as those described for theaforementioned amino group containing phenol derivative.

[0043] In the general formulas (2) and (3), R⁶ represents an aromatictetracarboxylic dianhydride group. Examples of preferred aromatictetracarboxylic dianhydrides include pyromellitic dianhydride,3,3′,4,4′-benzophenonetetracarboxylic dianhydride,2,2′,3,3′-benzophenonetetracarboxylic dianhydride,2,3,3′,4′-benzophenonetetracarboxylic dianhydride,naphthalene-2,3,6,7-tetracarboxylic dianhydride,naphthalene-1,2,5,6-tetracarboxylic dianhydride,naphthalene-1,2,4,5-tetracarboxylic dianhydride,naphthalene-1,4,5,8-tetracarboxylic dianhydride,naphthalene-1,2,6,7-tetracarboxylic dianhydride,3,3′,4,4′-diphenyltetracarboxylic dianhydride,2,2′,3,3′-diphenyltetracarboxylic dianhydride,2,3,3′,4′-diphenyltetracarboxylic dianhydride,3,3″,4,4″-p-terphenyltetracarboxylic acid,2,2″,3,3″-p-terphenyltetracarboxylic acid,2,3,3″,4″-p-terphenyltetracarboxylic acid,2,2-bis(2,3-dicarboxyphenyl)propane dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,bis(2,3-dicarboxyphenyl) ether dianhydride,bis(2,3-dicarboxyphenyl)methane dianhydride,bis(3,4-dicarboxyphenyl)methane dianhydride,bis(2,3-dicarboxyphenyl)sulfone dianhydride,bis(3,4-dicarboxyphenyl)sulfone dianhydride,1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, and1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride. Of these compounds,pyromellitic dianhydride, 3,3′,4,4′-diphenyltetracarboxylic dianhydrideare particularly preferred as they represent the most typical examples,and also offer low degrees of thermal expansion.

[0044] The mass average molecular weights of the polyimide precursor andthe polyimide polymer fall within the same range. The mass averagemolecular weight of each can be appropriately adjusted in accordancewith the desired application of the product, although values from 10,000to 100,000 are preferred, and values from 20,000 to 60,000 are even moredesirable. By controlling the reaction conditions, polyimide precursorsor polyimide polymers according to the present invention can be producedwith good control over the mass average molecular weight, to produce avalue within the aforementioned range from 10,000 to 100,000, andpreferably from 20,000 to 60,000. As a result, a molecular weight whichcompares favorably with those of conventional polyimide polymers can beachieved.

[0045] Furthermore, in addition to having a similar mass averagemolecular weight to conventional polyimide polymers, it was discoveredthat a polyimide polymer of the present invention also has the extremelyuseful characteristic of being soluble in organic solvents. In otherwords, typically, conventional aromatic polyimide polymers have beendifficult to dissolve in organic solvents. As a result, typically amethod is employed in which a polyimide precursor (namely a polyamicacid) which is soluble in organic solvents is prepared in advance, and asolution containing this polyimide precursor dissolved in an organicsolvent is then applied to a substrate, and is subsequently converted toa polyimide by heating to cause a cyclodehydration and subsequentdrying, thereby enabling the formation of a polyimide polymer film. Theconditions for the heating and drying treatment steps in this methodrequire a high temperature and a considerable length of time in order toachieve the cyclization of the polyimide precursor via a dehydrationcondensation and generate the product polyimide polymer. In contrast, apolyimide polymer of the present invention is soluble in organicsolvents, and consequently a polyimide polymer film can be produced byapplying a solution, not of a precursor, but rather of the polyimidepolymer itself generated by the dehydration condensation dissolved in anorganic solvent, and then performing a subsequent drying step at a farlower temperature and for a far shorter time period than the heating anddrying treatment conditions described above.

[0046] Consequently, a film can be produced in a far shorter time, andvia a far simpler operation than is conventionally possible.Furthermore, because only a solvent removal treatment is required, andthere is no need to conduct a dehydration condensation reaction, afurther benefit is obtained in that reductions in the film thickness orthe generation of irregularities in the film thickness caused bydehydration do not occur.

[0047] There are no particular restrictions on the organic solvent used,provided the solvent is capable of dissolving the polyimide polymers ofthe present invention, and either a single solvent, or a mixture of twoor more solvents may be used. Suitable solvents include organic solventssuch as N-methyl-2-pyrolidone, N,N-dimethylformamide,N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide,tetramethylene sulfone, γ-butyrolactone, and p-chlorophenol, as well asglyme based solvents such as methyldiglyme and methyltriglyme.

[0048] As described above, according to the present invention, polyimideprecursors and polyimide polymers can be provided which while retainingthe inherent advantages of conventional polyimide polymers, also offeradditional advantages in relation to film formation such as a simplerfilm formation process and a smoother film surface. In addition, apolyimide precursor of the present invention can be subjected to adehydration condensation reaction and converted to a polyimide polymer,before being dissolved in a solvent, applied to a substrate, andsubsequently dried to form a predetermined shape. Consequently, theproblem of dehydration condensation water being generated during theheating treatment, which arises in cases where a solution of a polyimideprecursor is first applied to a substrate, before being subjected to adehydration condensation reaction, can be avoided. As a result, voidsand the like, which can be generated during the-removal of water from amolded product such as a film, are less likely to occur. In thin films,water generated by the dehydration condensation reaction can readilyescape into the atmosphere, but in the case of thicker films or thickermolded products in the shape of rectangular prisms or the like, thewater is far more difficult to remove, and voids and the like becomemore likely. In these types of applications, it is preferable that asolution containing a dissolved polyimide polymer is used, as a uniformmolded product with no voids can be produced. As a result, polyimideprecursors and polyimide polymers of the present invention, even withoutmixing, offer excellent characteristics as aqueous developing materials,adhesives for electronic materials, insulating materials, and moldingmaterials and the like.

[0049] A polyimide precursor of the present invention can be produced inthe manner described below. First, an amino group containing phenolderivative and an organic solvent are placed in a reaction vessel, andthe mixture is stirred for approximately 30 minutes at room temperaturefor example, to dissolve the amino group containing phenol derivative.There are no particular restrictions on the organic solvent provided itis capable of uniformly dissolving the materials and reactants, andeither single solvents or mixtures of two or more solvents may be used.Suitable examples include organic solvents such asN-methyl-2-pyrolidone, N,N-dimethylformamide, N,N-dimethylacetamide,dimethylsulfoxide, hexamethylphosphoramide, tetramethylene sulfone,γ-butyrolactone, and p-chlorophenol, as well as glyme based solventssuch as methyldiglyme and methyltriglyme. Sufficient organic solvent isused to generate a concentration of the amino group containing phenolderivative of 10 to 35 mass %, and preferably 15 to 25 mass %.

[0050] Subsequently, with the temperature maintained at no more than 30°C. (and preferably at 20 to 25° C.), an aromatic tetracarboxylicdianhydride is added gradually with constant stirring, over a period of0.5 to 1 hour. The reaction mixture is then stirred at the sametemperature for a period of 1 to 20 hours, and yields a polyimideprecursor solution. In those cases in which the polyimide precursor isrequired, the solution should preferably be used, as is. The molar ratioof the amino group containing phenol derivative relative to the aromatictetracarboxylic dianhydride should be within a range from 1.2 to 0.9,and preferably approximately 1, and even more preferably from 1.01 to0.99.

[0051] In those cases in which the polyimide precursor is to besubsequently subjected to a dehydration condensation reaction togenerate a polyimide polymer, the polyimide precursor solution obtainedin the manner described above is heated for 2 to 4 hours at atemperature of 170 to 200° C., causing a dehydration condensationreaction and yielding a polyimide polymer.

[0052] (C) Photosensitive Polyimide Precursor and PhotosensitivePolyimide Polymer

[0053] A photosensitive polyimide precursor of the present invention isa polyimide precursor formed from a repeating unit represented by theaforementioned general formula (2) in which the hydrogen atom of atleast one phenolic hydroxyl group is substituted with a functional groupwhich imparts photosensitivity to the polyimide precursor. Aphotosensitive polyimide polymer of the present invention is a polyimidepolymer formed from a repeating unit represented by the aforementionedgeneral formula (3) in which the hydrogen atom of at least one phenolichydroxyl group is substituted with a functional group which impartsphotosensitivity to the polyimide polymer. These photosensitivepolyimide precursors and photosensitive polyimide polymers displayexcellent characteristics as aqueous developing materials, as solderresists for electronic materials, and as photosensitive materials.Because this type of photosensitive polyimide polymer has alreadyundergone a dehydration condensation reaction prior to film formation,water is not generated during the film formation, which offers aconsiderable advantage in that the film thickness does not reduce duringthe film formation process. As described above for polyimide polymers ofthe present invention, a photosensitive polyimide polymer of the presentinvention is particularly effective in cases where water is difficult toremove, such as in thicker films.

[0054] When a photosensitive polyimide precursor is used in alkalideveloping, large quantities of photosensitive groups may need to beintroduced in order to achieve appropriate contrast during the alkalideveloping process. In the case of a photosensitive polyimide precursor,from 10 to 90%, and preferably from 40 to 80% of the phenolic hydroxylgroups should be substituted with the aforementioned functional groupwhich imparts photosensitivity. In the case of a photosensitivepolyimide polymer, from 10 to 70%, and preferably from 20 to 40% of thephenolic hydroxyl groups should be substituted with the functional groupwhich imparts photosensitivity.

[0055] The mass average molecular weights of the photosensitivepolyimide precursor and the photosensitive polyimide polymer fall withinthe same range, and in order to achieve good applicability, values from10,000 to 100,000, and preferably from 20,000 to 60,000 are preferred.

[0056] Examples of functional groups which impart photosensitivity topolyimide precursors or polyimide polymers include quinonediazide basedphotosensitive groups and acryloyl groups. Specific examples ofpreferred quinonediazide based photosensitive groups include1,2-benzoquinonediazide-4-sulfonate esters,1,2-naphthoquinonediazide-4-sulfonate esters,1,2-naphthoquinonediazide-5-sulfonate esters,2,1-naphthoquinonediazide-4-sulfonate esters, and2,1-naphthoquinonediazide-5-sulfonate esters.

[0057] As an example, a photosensitive polyimide precursor of thepresent invention substituted with a quinonediazide based photosensitivegroup can be produced by preparing a polyimide precursor of the presentinvention using the method described above, and then reacting 100 partsby mass of this precursor with preferably 1 to 50 parts by mass, andeven more preferably 5 to 25 parts by mass of quinonediazide sulfonylchloride. In this reaction, it is preferable that following the additionof the quinonediazide sulfonyl chloride, an additional 1.2 equivalentsof triethylamine is added dropwise over a period of approximately 30minutes, at a temperature of no more than 30° C., and preferably no morethan 25° C., and is subsequently reacted for a period of 2 to 12 hours.Subsequently, the reaction mixture is poured into a large volume of a0.2% aqueous oxalic acid solution, equivalent to 10 times the volume ofthe reaction solution, and the precipitated solid fraction is filtered,washed with ion exchange water and then dried to yield thephotosensitive polyimide precursor. In addition, a photosensitivepolyimide polymer of the present invention substituted with aquinonediazide based photosensitive group, for example, can be producedin a similar manner to that described above, by first preparing apolyimide polymer of the present invention, and then reacting this resinwith quinonediazide sulfonyl chloride in a similar manner to theaforementioned photosensitive polyimide precursor. Furthermore, aphotosensitive polyimide polymer can also be produced by subjecting anaforementioned photosensitive polyimide precursor to a dehydrationcondensation reaction. A photosensitive polyimide precursor or aphotosensitive polyimide polymer substituted with an acryloyl group canbe produced in the same manner as that described above, with theexception of replacing the quinonediazide sulfonyl chloride with acrylylchloride.

[0058] Although dependent to some degree on the desired finalapplication of the product, the most preferred photosensitive polyimideprecursors and photosensitive polyimide polymers are those which use apreferred amino group containing phenol derivative shown in the above:

[0059] (n is preferably from 1 to 20). Of these, precursors and resinswhich utilize pyromellitic dianhydride or3,3′,4,4′-diphenyltetracarboxylic dianhydride as the aromatictetracarboxylic dianhydride are particularly preferred for thoseapplications in which the effects of thermal expansion are an importantfactor.

[0060] (D) Composite Materials

[0061] Polyimide precursors and polyimide polymers of the presentinvention can be converted to composite materials by complexing withother compounds. In the present invention, there are no particularrestrictions on these other compounds used in the formation of compositematerials provided they contain a functional group capable of reactingwith a phenolic hydroxyl group, and although the nature of the compoundwill vary depending on the application, synthetic resins and the likeare preferred. Specific examples include epoxy resins, silicone resinsand acrylic resins, and these resins may be used singularly, or inmixtures of two or more different resins. In the present invention,composite materials formed with epoxy resins or silicone resins canprovide additional favorable characteristics such as increased heatresistance, improved mechanical characteristics, electrical insulationand flame resistance of the polyimide polymer, as well as good filmmoldability, which are particularly desirable in electronic componentapplications such as surface protective films for semiconductor elementsand interlayer insulation films and the like. Furthermore, in thosecases in which any one of the groups R¹, R² and R³ in the generalformulas (2) and (3) is a COOR group, composite materials can also beformed with polyester resins. Of the polyimide precursors and thepolyimide polymers, complexing is possible for any precursor or resinwhich has at least one phenolic hydroxyl group, and consequentlycomplexing is also possible for photosensitive polyimide precursors orphotosensitive polyimide polymers with at least two phenolic hydroxylgroups, where a portion of the hydrogen atoms of these hydroxyl groupshave been substituted with a quinonediazide based photosensitive group.

[0062] A composite material can be produced using the sample methoddescribed below. First, a polyimide precursor or a polyimide polymer ofthe present invention and a compound for forming the composite materialare mixed uniformly. In the case of a compound such as an epoxy resinwith a glycidyl group, mixing is conducted for a period of 20 to 60minutes, and preferably approximately 30 minutes, at a temperature of 40to 80° C., and preferably a temperature of approximately 60° C.Subsequently, a catalyst such as triphenylphosphine, triethylamine orany other typical curing accelerator (although triphenylphosphine ispreferred) is added, and the mixture is stirred for 20 to 60 minutes,and preferably for approximately 30 minutes, at a temperature of 40 to80° C., and preferably a temperature of approximately 60° C., to causethe complexing reaction to proceed. The temperature is then raised to170 to 350° C., and that temperature is maintained for 3 to 5 hours tocure the material and produce the composite material. The curing can beconducted by, for example, maintaining a temperature of 180° C. for onehour, raising the temperature and then maintaining a temperature of 250°C. for a further one hour, and then raising the temperature again andmaintaining a temperature of 320° C. for yet another one hour. In thosecases where a film is to be formed, the composite material can beapplied to a substrate surface using spin coating or the like, prior tothe temperature raising and curing steps, and the material can then becured under similar conditions to those described above, enabling asubstrate bonded film to be produced with considerable ease.

[0063] The relative proportions of the polyimide precursor or polyimidepolymer of the present invention and the other compound during theproduction of a composite material can be altered appropriately inaccordance with the nature of the other compound used and the intendedfinal application, although in the case of the production of a compositematerial with a synthetic resin for example, ratios (mass ratios) withina range from 10:1 to 1:10, and preferably from 4:1 to 1:4 are used.

[0064] In the case of complexing with an epoxy resin, there are noparticular restrictions on the type of epoxy resin, which can beselected in accordance with the desired final application. Examples ofsuitable epoxy resins include phenol novolak type epoxy resins; o-cresolnovolak type epoxy resins; epoxides of bisphenol A, bisphenol S,bisphenol F and biphenol and the like; and glycidylamine type epoxyresins formed by reaction of a polyamine such as diaminophenylmethaneand epichlorohydrin, and these resins may be used singularly, or incombinations of two or more such resins. For example, in the case of anapplication to a molding material, any of the various novolak resins arepreferred, whereas in the case of applications to films or adhesives,dimer type epoxy resins using the various bisphenols are preferred. Theepoxy equivalence of the epoxy resin can be varied in accordance withthe intended application, although typical values are from 150 to 250,and preferably from 160 to 200. Composite materials formed by complexingan epoxy resin display a surprisingly large increase in the glasstransition point over the glass transition point of the polyimideprecursor prior to complexing, and the improvement in heat resistance ismarked. Accordingly, a material can be produced which not only has goodadhesion to electronic components such as substrates, but also displaysextremely good heat resistance.

[0065] For applications to electronic components, the epoxy resin shouldpreferably be selected from resins conventionally used in electroniccomponent applications. In such cases, the relative proportions of thepolyimide precursor or polyimide polymer of the present invention andthe epoxy resin are typically within a range from 4:1 to 1:4, andpreferably from 2:1 to 1:2 (mass ratios). Furthermore recently, filmlike materials have been proposed as IC sealing materials, and becausecomposite materials of the present invention display the excellent filmformation properties of a polyimide polymer, they can also be ideallyapplied to this type of application.

[0066] In the case of complexing with a silicone resin, there are noparticular restrictions on the type of silicone resin, which can beselected in accordance with the desired final application. The numberaverage molecular weight of the silicone resin can be altered inaccordance with the intended application, although typical values arewithin a range from 3,000 to 30,000, and preferably from 5,000 to20,000. Recently, with the increasing degree of integration inelectronic components, silicone resins are being used as low stressresins. Accordingly, by complexing a silicone resin, a film or the likecan be produced which offers good flexibility and low stress, and alsodisplays the favorable characteristics of a polyimide polymer, namely ahigh level of heat resistance, a favorable dielectric constant and goodfilm forming properties. In particular, the composite material has thefavorable film forming properties of a polyimide polymer, and alsoexhibits the flexibility of a silicone resin, and consequently is idealfor applications such as film like sealing materials and flexibleprinted circuit boards. In such cases, the silicone resin shouldpreferably be selected from resins conventionally used in electroniccomponent applications. Suitable examples include phenylmethyl siliconeresin, methyl silicone resin and modified silicone resin. In such cases,the relative proportions of the polyimide precursor or polyimide polymerof the present invention and the silicone resin are typically within arange from 10:10 to 10:1, and preferably from 10:4 to 10:2 (massratios).

[0067] In this manner, by forming a polyimide precursor or a polyimidepolymer using an amino group containing phenol derivative of the presentinvention, the introduction of a phenolic hydroxyl group enablescomposite materials to be formed by complexing with other materials,while the favorable polyimide polymer characteristics such as heatresistance, mechanical characteristics, electrical insulation and flameresistance can be retained. What is described here as complexing refersto a reaction of an aforementioned phenolic hydroxyl group of an aminogroup containing phenol derivative group with a functional group ofanother compound, resulting in bond formation. Complexing with anotherresin enables the favorable characteristics of this other resin to beimparted to the composite material. Specifically, complexing with anepoxy resin results in a material with a low thermal expansioncoefficient and good adhesion to substrates such as glass, metals andmetal oxides. In contrast, complexing with silicone resins provides amaterial which offers good adhesion to silicon wafers and glass plates,and also displays excellent flexibility. Furthermore, in a polyimideprecursor or a polyimide polymer using an amino group containing phenolderivative of the present invention, the hydrogen atoms of phenolichydroxyl groups can be substituted with a functional group which impartsphotosensitivity to the polyimide precursor or polyimide polymer,enabling the preparation of a photosensitive polyimide precursor or aphotosensitive polyimide polymer.

EXAMPLES

[0068] As follows is a more detailed description of the presentinvention based on a series of examples.

[0069] (Synthesis of Amino Group Containing Phenol Derivatives)

Synthetic Example 1

[0070] (1) Synthesis of a Dimethylolphenol Derivative

[0071] 2,2′-methylenebis(4-methyl-6-hydroxymethylphenol) shown below wassynthesized as a dimethylolphenol derivative, in the manner describedbelow.

[0072] 162 g of p-cresol and 360 g of a 50% aqueous formalin solutionwere placed in a 2 L four neck flask equipped with a thermometer, acondenser, a stirrer and a dropping funnel. 200 g of a 30 mass % aqueoussolution of NaOH was then added dropwise over a two hour period at atemperature of no more than 30° C. The temperature was then raised to60° C. and the mixture was reacted for 4 hours, before the temperaturewas once again cooled to a temperature of no more than 30° C. 900 g of a10 mass % aqueous acetic acid solution was then added dropwise toneutralize the reaction mixture, which precipitated a crude product.This crude product was filtered, washed with water (300 g of water wasused for each wash, and four separate washing operations wereperformed), and then dried under reduced pressure at a temperature ofless than 50° C. (approximately 40° C.) to yield the product. The yieldwas 200 g, and the product was a white powder.

[0073] (2) Synthesis of an Amino Group Containing Phenol Derivative

[0074] Using the product obtained above,2,2′-methylenebis{4-methyl-6-(3,5-dimethyl-4-aminobenzyl)phenol} shownbelow was synthesized as an amino group containing phenol derivative, inthe manner described below.

[0075] First, 200 g of the above product, 190 g of 2,6-dimethylaniline,3.0 g of oxalic acid, and 20 g of ethylcellosolve were placed in a 500ml four neck flask equipped with a thermometer, a condenser, and astirrer, and reacted for 4 hours at a temperature of 120° C. Thereaction mixture was then cooled and recrystallized from 800 g ofethylcellosolve to yield the amino group containing phenol derivative.The yield was 315 g, and the product was a pale yellow power.Identification of the compound was performed based on the mass spectrum,the IR spectrum, and the melting point. The melting point was measuredusing a DSC 220 manufactured by Seiko Instruments Inc., on a sample sizeof 3 to 5 mg, using a temperature range of 20 to 550° C., and raisingthe temperature at a rate of 10° C./min. The IR spectrum is shown inFIG. 1. The melting point for the product was 201° C.

[0076] Synthetic Example 2

[0077] (1) Synthesis of a Dimethylolphenol Derivative

[0078] 2,6-dihydroxymethyl-4-n-propylcarboxyphenol shown below wassynthesized.

[0079] With the exception of altering the conditions described below, aproduct was obtained using the same method as described in the syntheticexample 1. The product yield was 100 g of a white powder.

[0080] Initial reactants: 90 g of propyl p-hydroxybenzoate and 120 g ofa 50 mass % aqueous formalin solution.

[0081] Dropwise addition conditions: 67 g of a 30 mass % aqueoussolution of NaOH added over a two hour period at a temperature of nomore than 40° C.

[0082] Raised temperature reaction conditions: 3 hours at 75° C.

[0083] Neutralization conditions: 540 g of a 10 mass % aqueous aceticacid solution.

[0084] (2) Synthesis of an Amino Group Containing Phenol Derivative

[0085] Using the product obtained above,2,6-bis(3,5-dimethyl-4-aminobenzyl)-4-n-propylcarboxyphenol) shown belowwas synthesized as an amino group containing phenol derivative.

[0086] With the exception of altering the conditions described below, aproduct was obtained using the same method as described in the syntheticexample 1. The product yield was 125 g of a pale yellow power. The IRspectrum is shown in FIG. 2. Furthermore, the melting point of theproduct was 127.8° C.

[0087] Initial reactants: 72 g of the above product, 80 g of2,6-dimethylaniline, and 1.5 g of oxalic acid

[0088] Reaction conditions: 4 hours at 140° C.

Synthetic Example 3

[0089] (1) Synthesis of a Dimethylolphenol Derivative

[0090] 2,6-dihydroxymethyl-4-t-butylphenol shown below was synthesizedas a dimethylolphenol derivative.

[0091] With the exception of altering the conditions described below, aproduct was obtained using the same method as described in the syntheticexample 1. The product yield was 67 g of a reddish yellow powder.

[0092] Initial reactants: 61 g of p-methoxyphenol and 162 g of a 37 mass% aqueous formalin solution.

[0093] Dropwise addition conditions: 67 g of a 30 mass % aqueoussolution of NaOH added over a two hour period at a temperature of nomore than 40° C.

[0094] Raised temperature reaction conditions: 2 hours at 60° C.

[0095] Neutralization conditions: 540 g of a 10 mass % aqueous aceticacid solution. (2) Synthesis of an amino group containing phenolderivative

[0096] Using the product obtained above,2,6-bis(3,5-dimethyl-4-aminobenzyl)-4-t-butylphenol) shown below wassynthesized as an amino group containing phenol derivative.

[0097] With the exception of altering the conditions described below, aproduct was obtained using the same method as described in the syntheticexample 1. The product yield was 120 g of a pale red solid. The IRspectrum is shown in FIG. 3. Furthermore, the melting point of theproduct was 180.7° C.

[0098] Initial reactants: 32 g of the above product, 30 g of2,6-dimethylaniline, and 0.6 g of oxalic acid

[0099] Reaction conditions: 4 hours at 140° C.

[0100] Purification (recrystallization) conditions: 150 g ofethylcellosolve.

Synthetic Example 4

[0101] (1) Synthesis of a Dimethylolphenol Derivative

[0102] A resol type orthocresol resin shown below was prepared as adimethylolphenol derivative.

[0103] With the exception of altering the conditions described below, aproduct was obtained using the same method as described in the syntheticexample 1. The product yield was 100 g of a brown, viscous liquid.

[0104] Initial reactants: 81 g of o-cresol and 99 g of a 50 mass %aqueous formalin solution.

[0105] Dropwise addition conditions: 100 g of a 30 mass % aqueoussolution of NaOH added over a two hour period at a temperature of nomore than 30° C.

[0106] Raised temperature reaction conditions: 1 hour at 70° C.

[0107] Neutralization conditions: 450 g of a 10% aqueous acetic acidsolution.

[0108] (2) Synthesis of an Amino Group Containing Phenol Derivative

[0109] An orthocresol novolak with an aminobenzyl group at bothterminals shown below was synthesized as an amino group containingphenol derivative.

[0110] First, 100 g of the above product, 180 g of aniline, and 2.8 g ofoxalic acid were placed in a 500 ml four neck flask equipped with athermometer, a condenser, and a stirrer, and reacted for 4 hours at atemperature of 180° C. Any unreacted reactants were then removed over a30 minute period at −720 mmHg and 180° C. The product was then removedand yielded 250 g of a brown solid. The softening point was 113° C. TheIR spectrum is shown in FIG. 4. Furthermore, measurement of the massaverage molecular weight by GPC (gel permeation chromatography) revealeda value of 770.

[0111] (Synthesis of a Polyimide Precursor)

Synthetic Example 5

[0112] Using the amino group containing phenol derivative obtained inthe synthetic example 1, a polyimide precursor was synthesized in themanner described below.

[0113] 4.940 g of the amino group containing phenol derivative obtainedin the synthetic example 1 and 40.30 g of NMP solvent(N-methylpyrolidone) were placed in a reaction vessel, and the aminogroup containing phenol derivative was dissolved by stirring for 30minutes at room temperature. Subsequently, 2.180 g of pyromelliticdianhydride was added at a temperature of no more than 30° C., and thereaction mixture was then stirred for 24 hours at a temperature of 25 to28° C. to yield a polyimide precursor. The IR spectrum is shown in FIG.5. The mass average molecular weight of the product was 34,500.

[0114] (Synthesis of a Polyimide Varnish)

Synthetic Example 6

[0115] Using the amino group containing phenol derivative obtained inthe synthetic example 4, a polyimide varnish (a polyimide polymersolution) was synthesized in the manner described below.

[0116] 6.180 g of the amino group containing phenol derivative obtainedin the synthetic example 4 and 32.57 g of NMP solvent were placed in areaction vessel, and the amino group containing phenol derivative wasdissolved by stirring for 30 minutes at room temperature. Subsequently,2.180 g of pyromellitic dianhydride was added at a temperature of nomore than 30° C., and the reaction mixture was stirred for one hour.Under an atmosphere of nitrogen, the temperature was then graduallyraised to 180° C. over a one hour period, and a dehydration condensationreaction (a cyclodehydration) was then performed over a 3 hour period toyield a polyimide varnish. The IR spectrum of the product is shown inFIG. 6. Furthermore, the mass average molecular weight of the productwas 32,000.

[0117] (Synthesis of a Polyimide Precursor for Use in a ComparativeExample 2, Described Below)

Synthetic Example 7

[0118] Using 4.00 g of p,p′-methylenedianiline, 4.36 g of pyromelliticdianhydride and 47.3 g of NMP solvent, a polyimide precursor wasprepared using the same method as that described for the syntheticexample 5.

[0119] (Synthesis of a Polyimide Precursor for use in a ComparativeExample 3, Described Below)

Synthetic Example 8

[0120] 20.0 g (0.10 mol) of p,p′-methylenedianiline and 6.00 g (0.001mol) of α,ω-bis(3-aminopropyl)polydimethylsiloxane with a mass averagemolecular weight of 6000 were dissolved in 272 g of NMP solvent, 22.02 g(0.101 mol) of pyromellitic dianhydride was added, and the mixture wasreacted for 24 hours to yield a polyimide precursor.

Example 1

[0121] (Complexing of the Polyimide Precursor of Synthetic Example 5 andan Epoxy Resin)

[0122] 10 g of an epoxy resin (Epikote 828 (a brand name of Yuka ShellEpoxy Co., Ltd.)) and 50 g of the polyimide precursor produced in thesynthetic example 5 were mixed for 30 minutes at 60° C. to produce auniform mixture, and 0.1 g of triphenylphosphine was then added as acatalyst, and the mixture was stirred for a further 30 minutes at 60° C.The thus obtained composite polyimide precursor solution was applied toa silicon wafer and a Cu substrate using spin coating techniques, andthen subjected to heat treatment for 1 hour at 180° C. and 1 hour at250° C., to yield polyimide-epoxy complexed polymer film. The IRspectrum of this polyimide film is shown in FIG. 7. The polyimide filmcoated silicon wafer was then subjected to 48 hours of heat treatment ina pressure cooker at a temperature of 121° C. and 100% RH, and a crosscut peeling test was performed both prior to, and following this heattreatment (in Table, these results are recorded as “pre PCT” and “postPCT” respectively). The results revealed that peeling did not occur, andthat a good level of adhesion was maintained. The aforementioned crosscut peeling test is performed by using a cutter to cut the film into 100separate 5 mm×5 mm squares, sticking a cellophane adhesive tape to thefilm, and then pulling away the cellophane and recording the number ofsquares which are peeled away with the cellophane. The same test wasalso performed using the Cu substrate sample. The results are shown inTable 1.

[0123] The glass transition point, the thermal decomposition temperature(differential scanning calorimetry [DSC]), and the coefficient of linearthermal expansion were also measured for the above product, using thetechniques outlined below. The aforementioned composite polyimideprecursor solution was applied to aluminum foil by roll coating, andfollowing heat treatment, was peeled off the aluminum foil to yield afilm of thickness 50 μm. The glass transition point and the coefficientof linear thermal expansion were measured using this film. Specifically,the measurements were performed using a TMA (brand name, manufactured bySII), under conditions including a temperature of 200 to 400° C., a rateof temperature increase of 2° C./min., a loading of 10 g. The thermaldecomposition temperature was measured using a TG/DTA 320 (brand name,manufactured by SII), under conditions including a sample size of 10 mg,a temperature of 100 to 800° C., and a rate of temperature increase of10° C./min.

[0124] For the purposes of comparison, the polyimide precursor producedin the synthetic example 7 was combined in a 1:1 ratio (mass ratio) withthe epoxy resin used in the example 1, and then complexed in the samemanner as described in the example 1, and the resulting product wassubjected to the same tests as above (comparative example 1).Furthermore, the same tests were also performed on the uncomplexedgeneral purpose polyimide polymer (comparative example 2). The glasstransition point was also determined for the polyimide polymer producedby subjecting the polyimide precursor of the example 1 to a dehydrationcondensation reaction. The results are shown in Table 1. TABLE 1Comparative Comparative Polyimide (prior Example 1 example 1 example 2to complexing) Glass transition point (° C.) 394 180 284 292 Thermaldecomposition 500 300 520 500 temperature (10% mass loss) (° C.)Coefficient of linear thermal 3.2 4.0 4.6 4.3 expansion (units: 10⁻⁴)Adhesion Tests (Cross cut peeling tests) Cu Pre PCT 100/100 22/100 0/100 0/100 Post PCT 100/100 0/100 0/100 0/100 Silicon wafer Pre PCT100/100 8/100 0/100 0/100 Post PCT 100/100 0/100 0/100 0/100

[0125] The results in Table 1 confirm that the composite material has ahigher glass transition point and better heat resistance than theuncomplexed polyimide polymer. Furthermore, the adhesion of thecomposite material was also excellent. In addition, the coefficient oflinear thermal expansion was small, and the variation in volume uponvariations in temperature was also small.

Example 2

[0126] (Complexing of the Polyimide Precursor of Synthetic Example 5 anda Silicone Resin)

[0127] 2.0 g of a silicone resin (KF1001 (a brand name of Shin-EtsuChemical Co., Ltd.) and 50 g of the polyimide precursor produced in thesynthetic example 5 were mixed in a similar manner to the example 1, and0.01 g of triphenylphosphine was then added as a catalyst, and theresulting mixture was reacted for 1 hour at 150° C. A sample was thenextracted, and a flexibility test was conducted in the manner describedbelow. The remaining reaction mixture was then reacted for a further 3hours at 180° C. to complete the reaction, and following cooling, waspoured into a large quantity of methanol. The precipitate that formedwas filtered and dried and the resulting product was removed. The IRspectrum of the product is shown in FIG. 8. The formation of a complexedcomposite material was confirmed by the Si—O peak at 1000 to 1200 cm⁻¹.The mass average molecular weight of the composite material was 37,000.Measurement of the glass transition point in a similar manner to theexample 1 produced a value of 260° C.

[0128] (Stress Measurement: Evaluation of Flexibility)

[0129] The polyimide precursor produced in the example 2 was spin coatedon to a 5 inch silicon wafer, and then subjected to heat treatment for 3hours at 180° C. to form a polyimide film. The radius of curvature ofthe 5 inch wafer was then measured, and the formula shown below was usedto calculate the stress on the silicon wafer. In addition, as acomparative example 3, the polyimide precursor produced in the syntheticexample 8 was also spin coated on to a 5 inch silicon wafer to form apolyimide film under the same conditions, and the radius of curvature ofthis 5 inch wafer was also measured, and the formula shown below wasused to calculate the stress on the silicon wafer, in an identicalmanner. The results are shown in Table 2.$\sigma_{f} = {\frac{t_{s}^{2}}{6\quad t_{f}R} \times \frac{E_{S}}{1 - r_{s}}}$

[0130] σ_(f): generated stress (kg/mm²)

[0131] t_(s): silicon wafer thickness (μm)

[0132] t_(f): film thickness (μm)

[0133] R: radius of curvature (μm)

[0134] E_(s): Young's modulus for silicon wafer (dyne/cm²)

[0135] r_(s): Poisson's ratio for silicon wafer (no units) TABLE 2Comparative Example 2 example 3 glass transition point 260 182 (° C.)generated stress 2.0 2.1 (kg/mm²) film thickness 10 10

[0136] From the results in Table 2, it is evident that a combination oflow stress and a high glass transition point (heat resistance) has beenachieved in the example 2. In contrast, in the comparative example 3,although a low stress was achieved, the siloxane units of the mainskeleton have reduced the glass transition point, resulting in anunsatisfactory heat resistance.

Example 3

[0137] (Synthesis of a Photosensitive Polyimide polymer)

[0138] 26.7 g of the polyimide varnish produced in the synthetic example6 was placed in a reaction vessel, 0.269 g of1,2-naphthoquinone-2-diazide-5-sulfonyl chloride was added, and themixture was stirred to produce a uniform mixture. With the reactionvessel cooled, 1.01 g of triethylamine diluted with acetone solvent to aconcentration of 10 mass % was then added dropwise over a 30 minuteperiod, and following completion of the addition, the reaction waspermitted to proceed for 24 hours at room temperature. Followingcompletion of the reaction, the reaction liquid was poured into 250 g ofa 0.02 mass % aqueous oxalic acid solution, and the precipitated yellowcolored solid was filtered, washed with ion exchange water, and thendried to yield a photosensitive polyimide polymer. The IR spectrum ofthis product is shown in FIG. 9. The IR spectrum confirmed that aphotosensitive group had been introduced into the resin. 3.0 g of thisphotosensitive polyimide polymer was dissolved in 12 g ofethylcellosolve to prepare a 20 mass % solution. This photosensitivepolyimide polymer solution was spin coated onto a silicon wafer, andfollowing heating for 10 minutes on a 90° C. hot plate, the filmthickness was measured and revealed a thickness of 5.2 μm. The film wasthen irradiated with 65 mJ/cm² of 365 nm radiation from a UV exposuredevice (ML-251C/A, manufactured by Ushio Inc.), subsequently immersed ina 1.98% aqueous TMAH solution (tetramethylammonium hydroxide) for 60seconds, and then washed with water for 20 seconds. The film thicknessof the exposed portion and the unexposed portion were measured, and aresidual film ratio was determined. The results were 0% for the exposedportion and 100% for the unexposed portion.

[0139] As described above, according to the present invention, by usingan amino group containing phenol derivative with a phenolic hydroxylgroup, composite materials can be formed with other compounds, and avariety of materials can be provided which, while retaining thefavorable characteristics of polyimide polymers, also display additionalcharacteristics not obtainable using solely a polyimide.

What is claimed is:
 1. An amino group containing phenol derivativerepresented by a general formula (1) show below:

(wherein, R¹, R² and R³, which may be identical or different, eachrepresent an alkyl group of 1 to 9 carbon atoms, an alkoxy group of 1 to10 carbon atoms, a COOR group (in which R represents an alkyl group of 1to 6 carbon atoms) or a hydrogen atom; R⁴ and R⁵, which may be identicalor different, each represent an alkyl group of 1 to 9 carbon atoms or ahydrogen atom; X represents —O—, —S—, —SO₂—, —C(CH₃)₂—, —CH₂—,—C(CH₃)(C₂H₅)—, or —C(CF₃)₂—; and n represents an integer of 1 orgreater).
 2. An amino group containing phenol derivative according toclaim 1, wherein said R⁴ groups, said R⁵ groups, and said X and —CH₂—groups bonded to respective terminal benzene rings are bonded to anidentically numbered carbon atom in each case (numbers showing carbonatom position are shown in said general formula (1)).
 3. An amino groupcontaining phenol derivative according to claim 1, wherein X is a —CH₂—group.
 4. An amino group containing phenol derivative according to claim1, wherein R⁴ and R⁵ are methyl groups.
 5. An amino group containingphenol derivative according to claim 1, wherein either one or two of R¹,R² and R³ are hydrogen atoms, and a remainder are groups other thanhydrogen atoms.
 6. An amino group containing phenol derivative accordingto claim 5, wherein said groups other than hydrogen atoms are methylgroups.
 7. An amino group containing phenol derivative according toclaim 1, wherein all of R¹, R² and R³ are methyl groups.
 8. A polyimideprecursor formed from a repeating unit represented by a general formula(2) shown below:

(wherein, R¹, R² and R³, which may be identical or different, eachrepresent an alkyl group of 1 to 9 carbon atoms, an alkoxy group of 1 to10 carbon atoms, a COOR group (in which R represents an alkyl group of 1to 6 carbon atoms) or a hydrogen atom; R⁴ and R⁵, which may be identicalor different, each represent an alkyl group of 1 to 9 carbon atoms or ahydrogen atom; X represents —O—, —S—, —SO₂—, —C(CH₃)₂—, —CH₂—,—C(CH₃)(C₂H₅)—, or —C(CF₃)₂—; R⁶ represents an aromatic tetracarboxylicdianhydride group; and n represents an integer of 1 or greater).
 9. Apolyimide precursor according to claim 8, wherein said R⁴ groups, saidR⁵ groups, and said X and —CH₂— groups bonded to respective terminalbenzene rings with bonded amino groups are bonded to an identicallynumbered carbon atom in each case (numbers showing carbon atom positionare shown in said general formula (2)).
 10. A polyimide precursoraccording to claim 8, wherein X is a —CH₂— group.
 11. A polyimideprecursor according to claim 8, wherein R⁴ and R⁵ are methyl groups. 12.A polyimide precursor according to claim 8, wherein either one or two ofR¹, R² and R³ are hydrogen atoms, and a remainder are groups other thanhydrogen atoms.
 13. A polyimide precursor according to claim 12, whereinsaid groups other than hydrogen atoms are methyl groups.
 14. A polyimideprecursor according to claim 8, wherein all of R¹, R² and R³ are methylgroups.
 15. A polyimide polymer obtained by performing a dehydrationcondensation reaction on a polyimide precursor according to claim
 8. 16.A photosensitive polyimide precursor, wherein a hydrogen atom of atleast one phenolic hydroxyl group of a polyimide precursor according toclaim 8 is substituted with a functional group which impartsphotosensitivity to said polyimide precursor.
 17. A photosensitivepolyimide polymer obtained by performing a dehydration condensationreaction on a photosensitive polyimide precursor according to claim 16.18. A photosensitive polyimide polymer, wherein a hydrogen atom of atleast one phenolic hydroxyl group of a polyimide polymer according toclaim 15 is substituted with a functional group which impartsphotosensitivity to said polyimide polymer.
 19. A composite materialobtained by complexing a polyimide precursor or a polyimide polymeraccording to claim 8 with another compound.
 20. A composite materialaccording to claim 19, wherein said another compound comprises an epoxyresin.
 21. A composite material according to claim 19, wherein saidanother compound comprises a silicone resin.